Print head check method and image forming apparatus

Abstract

A printer has a print head check unit that performs an ink ejection check to confirm whether or not ink is being ejected normally from nozzles, based on induced voltage generated when charged ink droplets are ejected onto a check area. Upon receipt of a print instruction (S 100 ), the printer sets a flag F to 1 so as to start an ink ejection check and starts a paper feed process (S 110 ). When the processes has been terminated (S 120 , S 130 ), the printer starts printing. Accordingly, as an ink ejection check takes place concurrently with the paper feed process, the overall time required for the processes can be reduced, in comparison with any method in which the processes are executed separately. In this way, because of efficient implementation, the overall time required for the processes of the ejection check of the print recording liquid and an image forming process can be reduced. In addition, the ink ejection check may be performed in parallel with or partly overlapping with a process of receiving print data, a process of conversion into print data, a process of ejecting paper after printing, or a flashing process, etc.

1. An image forming method by using an image forming apparatus that performs printing by using a print head including a plurality of nozzles that eject a print recording liquid onto a print medium, the image forming method comprising:
 performing an ejecting check using light beams, and 
 executing a process of ejecting print medium for which the printing is completed when any subsequent pages to be printed exist, 
 wherein the ejection check is performed during the process, 
 wherein the ejecting check determines whether each of the nozzles of the print head ejects normally, and 
 wherein the ejection check performed in parallel with, or in a partially overlapping manner with, any one process of the executing the process, said one process is selected from a reception process of receiving printing instruction from a user, a data conversion process of converting data for which printing is instructed into print data, a supply process of supplying the print medium to a position at which the print head ejects the print recording liquid, a print medium ejection process of ejecting a print medium that has completed printing, an edge detection process of ejecting a print medium that has completed printing, an edge detection process of detecting an edge of the print medium supplied to the position in which the print head ejects the prim recording liquid during printing on a first page, and a flashing process of executing a flashing process which forcibly ejects the print recording liquid from each of the nozzles of the print head in a predetermined flashing area. 
 
     
     
       2. The image forming method of  claim 1 , further comprising a process that is not related to the ejection of the print recording liquid from the nozzles. 
     
     
       3. The image forming method of  claim 2 , the method further comprises receiving a printing instruction from a user. 
     
     
       4. The image forming method of  claim 2 , the method further comprises converting data for which a printing is instructed into print data. 
     
     
       5. The image forming method of  claim 1 , the method further comprises executing an edge detection process for detecting an edge of the print medium provided at a position where the print head ejects the print recording liquid. 
     
     
       6. The image forming method of  claim 5 , wherein
 the image forming apparatus includes a print head travel module capable of moving the print head in a main scanning direction substantially orthogonal to a transport direction of the print medium, and an edge detection process module that is included in the print head and is capable of detecting one of two edges of the print medium at a first detection position in a vicinity of a predetermined initial position and detecting the other of the two edges at a second detection position, and 
 the method further comprises causing the print head travel module to move the print head from the initial position to the first detection position and enables the edge detection process module to detect one of the two edges at the first detection position, then causes the print head travel module to move the print head from the first detection position to the second detection position and enables the edge detection process module to detect the other of the two edges at the second detection position, subsequently causes the print head travel module to move the print head to the check area that is provided near the second detection position and performs the ejection check in the check area, and then causes the print head travel module to move the print head back to the initial position. 
 
     
     
       7. The image forming method of  claim 1 , comprises performing a flashing process which forcibly ejects the print recording liquid from each of the nozzles of the print head in a predetermined flashing area. 
     
     
       8. The image forming method of  claim 7 , wherein:
 the image forming apparatus includes a print head travel module capable of moving the print head in a main scanning direction substantially orthogonal to a transport direction of the print medium, and 
 the method further performs either one of the following processes i) and ii): 
 i) causing the print head travel module to move the print head from an initial position, which is on the side of an exterior range to a specific edge of the print medium, to the flashing area in the vicinity of the check area, which is provided on the side of an exterior range to an opposite edge of the print medium to the specific edge, and performs the flashing process, subsequently causing the print head travel module to move the print head to the check area and performs the ejection check, and then causing the print head travel module to move the print head back to the initial position, 
 ii) causing the print head travel module to move the print head from the initial position, which is on the side of an exterior range to a specific edge of the print medium, to the check area, which is provided on the side of an exterior range to an opposite edge of the print medium to the specific edge, and performs the ejection check, subsequently causing the print head travel module to move the print head to the flashing area in the vicinity of the check area and executes the flashing process, and then causing the print head travel module to move the print head back to the initial position. 
 
     
     
       9. The image forming method according to  claim 1 , wherein the executed process is a process of feeding said any subsequent pages to be printed. 
     
     
       10. An image forming apparatus that performs printing by ejecting print recording liquid onto a print medium, the image forming apparatus comprising:
 a print head having a plurality of nozzles that eject the print recording liquid; 
 a print head check module that performs an ejection check using light beams; and 
 a module that executes a process of ejecting print medium for which the printing is completed when any subsequent pages to be printed exist, 
 wherein the ejection check is performed during the process, 
 wherein the ejecting check determines whether each of the nozzles of the print head ejects normally, and 
 wherein the print head check module performs the ejection check in parallel with, or in a partially overlapping manner with, any one process performed by the module executing the process, where said one process, performed by the module executing the process, is selected from a reception process of receiving printing instruction from a user, a data conversion process of converting data for which printing is instructed into print data, a supply process of supplying the print medium to a position at which the print head ejects the print recording liquid, a print medium ejection process of ejecting a print medium that has completed printing, an edge detection process of ejecting a print medium that has completed printing, an edge detection process of detecting an edge of the medium supplied to the position in which the print head ejects the print recording liquid during printing on a first page, and a flashing/process of executing flashing process which forcibly ejects the print recording liquid from each of the nozzles of the print head in a predetermined flashing area. 
 
     
     
       11. The image forming apparatus of  claim 10 , wherein the module that executes the process executes a process that is not related to the ejection of the print recording liquid from the nozzles. 
     
     
       12. The image forming apparatus of  claim 10 , wherein
 the module that executes the process is any one module selected from a reception module for receiving printing instruction from a user, a data conversion module for converting data for which printing is instructed into print data, a supply module for supplying the print medium to a position at which the print head ejects the print recording liquid, an edge detection module for detecting an edge of the print medium supplied to the position at which the print head ejects the print recording liquid during printing on a first page, and a flashing module for executing a flashing process which forcibly ejects the print recording liquid from each of the nozzles of the print head in a predetermined flashing area. 
 
     
     
       13. The image forming apparatus of  claim 10 ,
 further comprising a print head travel module that moves the print head in a main scanning direction substantially orthogonal to a transport direction of the print medium, wherein 
 the module that executes the process is an edge detection module included in the print head and that detects an edge of the print medium supplied at a position to which the print head ejects the print recording liquid, and that is capable of detecting one of two edges at a first detection position in the vicinity of a predetermined initial position, and detecting the other of the two edges at a second detection position, and 
 the print head check module drives the print head to eject the print recording liquid onto the check area provided near the second detection position, 
 the control module causes the print head travel module to move the print head from the initial position to the first detection position and the edge detection process module to detect one of the two edges at the first detection position, causes the print head travel module to move the print head from the first detection position to the second detection position and the edge detection process module to detect the other of the two edges at the second detection position, causes the print head travel module to move the print head to the check area, causes the print head check module to perform the ejection check in the check area, and then causes the print head travel module to move the print head back to the initial position. 
 
     
     
       14. The image forming apparatus of  claim 10 ,
 further comprising a print head travel module that moves the print head in a main scanning direction substantially orthogonal to a transport direction of the print medium, wherein 
 the module that executes the process is a flashing module that executes a flashing process which forcibly ejects the print recording liquid from each of the nozzles of the print head in a flashing area which is located in the vicinity of the check area that is opposite to the predetermined initial position with the print medium sandwiched therebetween, and 
 the control module causes the print head travel module to move the print head from the initial position to the flashing area and the flashing process module to execute the flashing process, and subsequently causes the print head travel module to move the print head to the check area and the print head check module to perform the ejection check, or otherwise causes the print head travel module to move the print head from the initial position to the check area and the print head check module to perform the ejection check, and subsequently causes the print head travel module to move the print head to the flashing area and the flashing process module to execute the flashing process, and then causes the print head travel module to move the print head back to the initial position. 
 
     
     
       15. The image forming apparatus according to  claim 10 , wherein the module that executes the process executes a process of feeding said any subsequent pages to be printed.